I've got three recordings of this now: Charles Munch's 1959 recording which in remastered form is critically acclaimed but lacks the thunderous tympani required for the Tuba Mirum (presume that the recording technology of the day wouldn't cope); James Levine's 1992 version with Pavarotti which has the thunder but very muted brass and, tenor solos apart, is less convincing overall and now Paul McCreesh.
I've liked virtually all of McCreesh's work so needed little convincing to buy. Typically, he goes for it in a big way with huge forces of over 400 (it requires tenor solo, chorus - his has over 200 voices, large orchestra and four brass ensembles) but absolutely nails it with subtlety in the quieter sections to counterbalance the fire and brimstone. For me, this is the one I've been waiting for. It is a little slower than the other versions (overall 3-4 minutes longer than the other versions I own), but never drags.
Typically, the attention to detail is what colours the sound and makes this such a vital recording. For example, he uses 16 nineteenth century tympani and had sticks specially made in the style that would have been used in Belioz's day. You can also expect period brass including the Ophicleide. He was however defeated when trying to source 100 gut strung stringed instruments, but ensures that they are played in a period style. All very typical McCreesh and a must have for your collection.